The present invention relates to an angular connection for frames and counterframes formed of hollow plastic sections.
The invention also relates to a process for producing such a connection, based essentially on welding by the ultrasonic technique.
In the description hereinbelow, frames and counterframes are understood to be both sashes and countersashes for inside and ourside frames, and framework of any other kind, provided it is made of plastic hollow sections.
In the manufacture of sashes made of hollow plastic sections, there is a problem involving the angle connection.
For this purpose, it is usual to assemble sections cut at 45.degree. by welding the edges in the vicinity of the angle or by force-fitting angular elements into the interiors of the sections converging in the vicinity of this angle.
In the latter case, adhesives or self-tapping screws are also used to ensure a better grip.
These known methods are not entirely satisfactory.
Thus, for example, it is usually difficult to operate with the desired precision when welding the edges of the sections, and the use of screws can impair the mechanical characteristics of the sash thus produced.
In any event, when known techniques are used, there are disadvantages deriving both from the large number and difficulty of the operations and from the time required for such operations.
Consequently, the rate of production is low and the cost is high.
Finally, the machinery used to manufacture such sashes is often complex.